/Engine/Plugins/Runtime/MassEntity/Source/MassEntity/Public/MassProcessingTypes.h
Goes through Processor looking for aUMassCompositeProcessorinstance which GroupName matches the one given as the parameter
[UMassCompositeProcessor](API\Plugins\MassEntity\UMassCompositeProcessor) * FindTopLevelGroupByName ( const [FName](API\Runtime\Core\UObject\FName) GroupName )